Mold and method for manufacturing drawn can

Abstract

A mold used for blanking a metal plate to shape a blank to be drawn. The mold has a surface treatment film and a top face to be brought into contact with the metal plate and a peripheral end face communicated indirectly with the top face. At least the top face is coated with the surface treatment film.

The invention claimed is: 
     
       1. A mold applicable to blanking of a plate material for shaping a blank to be drawn and to drawing the blank, said mold being an annular mold with a through hole to pass a drawing punch, comprising:
 (i) a top face to be brought into contact with the plate material and a peripheral end face, and wherein 
 (ii) a peripheral wall face is provided downward from an outer edge of the top face, the peripheral end face being connected to the top face by the peripheral wall face, 
 (iii) a lower end of the peripheral wall face joins the peripheral end face, 
 (iv) a corner formed by the peripheral wall face and the outer edge of the top face is rounded, 
 (v) a diameter of an outer edge of the peripheral end face and a diameter of an outer edge of the mold are the same, and the diameter of the outer edge of the mold corresponds to a diameter of the blank to be drawn, and 
 (vi) at least the top face is coated with a diamond film, 
 wherein the outer edge of the peripheral end face is a cutting edge for blanking the plate material. 
 
     
     
       2. The mold according to  claim 1 , wherein a groove is formed in a region between the outer edge of the top face and an inner edge of the peripheral end face. 
     
     
       3. The mold according to  claim 1 , wherein the top face and the peripheral end face are constituted of separate members. 
     
     
       4. The mold according to  claim 1 , wherein the top face has a surface roughness Ra of not more than 0.1 μm. 
     
     
       5. The mold according to  claim 1 , wherein the top face and the peripheral end face are coated with the diamond film. 
     
     
       6. The mold according to  claim 1 , wherein the top face, the peripheral wall face and the peripheral end face are coated with the diamond film. 
     
     
       7. The mold according to  claim 6 , wherein a groove is formed in a circumferential direction on at least one of the peripheral end face and the peripheral wall face. 
     
     
       8. The mold according to  claim 1 , wherein the peripheral end face has an outer periphery that is not coated with the diamond film. 
     
     
       9. A method for manufacturing a drawn can, comprising the steps of:
 (i) preparing the mold according to  claim 1 , 
 (ii) using the mold as a punch to blank a plate material to form a blank, and 
 (iii) subsequently using the mold as a die to draw the blank with the drawing punch.